JPH0475946B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a plating base adhesive for forming a metal film with good adhesion by chemical metal plating. [Prior art] In general, laminates for additive plating include:
Made of curable resin containing synthetic rubber, thickness 20~
The surface is coated with a 50μm adhesive layer. That is, this adhesive-coated substrate can be processed into a printed wiring board by a well-known additive plating process. In this case, in order to obtain strong adhesion between the plated metal and the adhesive,
Roughening the synthetic rubber component in the adhesive by dissolving it with a chromic acid/sulfur solution, etc. to form a porous surface;
Forming radicals and as hydrophilic groups =
Forming C=O, -OH, etc. is commonly practiced. However, when forming a metal film of 20 to 40 μm by chemical plating, plating blisters occur due to the stress of plating. Further, the adhesion between the metal film and the adhesive layer is about 1.5 to 2.5 kg/cm, which is not necessarily sufficient. Furthermore, there were also problems in heat softening of the adhesive film and in processability. [Object of the Invention] The present invention was completed as a result of studies aimed at improving and improving the adhesion between the plated metal film and the adhesive layer in the conventional additive method.
The purpose is to provide an adhesive for additive plating that has good adhesion between the adhesive layer and the metal plating film and is also improved in terms of heat resistance and processability. [Structure of the Invention] The present invention provides an adhesive for additive plating made of a curable resin containing synthetic rubber, which is characterized in that an inorganic filler surface-treated with a resol type phenolic resin or a fatty acid is added. It is an adhesive for attaching. As the synthetic rubber, acrylonitrile butadiene rubber (NBR), butadiene rubber (BR), styrene butadiene rubber (SBR), etc. can be used. Curable resins include thermosetting resins and photocurable resins. As the thermosetting resin, phenol resin, epoxy resin, melamine resin, etc. can be used. As the photocurable resin, polymers of acrylic esters of polyhydric alcohols such as trimethylolpropane triacrylate and pentaerythritol triacrylate can be used. The blending ratio of synthetic rubber and curable resin is
30~70% (weight%, same below), curable resin 70~
30% is preferred. If the synthetic rubber content is less than 30%, the surface cannot be sufficiently roughened with an oxidizing agent in the plating pretreatment, and the surface of the adhesive layer cannot be made porous. On the other hand, if the synthetic rubber content exceeds 70%,
The heat resistance as a printed wiring board deteriorates, making it difficult to put it into practical use. Next, as the inorganic filler surface-treated with resol type phenolic resin or fatty acid, which is a feature of the present invention, an inorganic filler such as silica, titanium oxide, alumina, etc. is added to the solution of the resol type phenolic resin or fatty acid. It is obtained by dipping, drying, and baking. Resol type phenolic resin or fatty acid is -OH
group or -COOH group, by adding such a functional group to the inorganic filler,
When adding palladium (Pd) catalyst in the plating process,
Since the adhesion between Pd and adhesive is significantly improved,
When chemical copper plating is performed in the post-process, peeling of the plating metal film due to plating stress is eliminated. The amount of inorganic filler added is not particularly limited, but
It is preferably 1 to 30% based on the solid content of the adhesive. 1%
Below this, the effect of improving the adhesion of the Pd catalyst is small;
If it exceeds 30%, the viscosity of the adhesive tends to increase, making it less practical. The particle size of the inorganic filler is usually 20μm or less,
Particularly preferred is 0.01 to 10 μm. When the particle size exceeds 20 μm, the surface area of the filler decreases, making it difficult to achieve the intended purpose. Particle size is 0.01~
At 10 μm, the adhesion of the plated metal film is particularly good, and the viscosity of the adhesive does not increase significantly, making it the most preferred for practical use. [Effects of the Invention] The adhesive for additive plating obtained by the present invention has the following features. (1) Since the adhesion with the Pd particles in the plating pretreatment is good, the adhesion between the plating metal and the adhesive layer is excellent. (2) Due to the reinforcing effect of the inorganic filler, the adhesive film becomes physically hard and has good heat deformation resistance. (3) Good workability in the hole-drilling or punch-pressing step performed after coating the surface of the laminate with the adhesive. (4) Since the filler has a functional group, sedimentation and separation of the filler in the adhesive can be prevented. [Examples] The adhesive for additive plating according to the present invention will be explained below using Examples and Comparative Examples. Example 1 NBR 50g Resol type phenolic resin 50g Silica whose surface is coated with resol type phenolic resin (particle size 3 to 5 μm, number of functional groups ₁₀₉ / ^m2 ) 3g Methyl ethyl ketone 200g The above resin mixture was mixed into an epoxy resin/glass cloth laminate. to form an adhesive layer with a thickness of 40μ. This adhesive-coated laminate was chemically plated with copper to a thickness of 30 μm using a conventional additive method. Example 2 NBR 50g Epoxy resin (Epon828) 50g Hardening agent (dicyandiamide) 5g Talc coated with caproic acid (particle size 3~
5 μm, number of functional groups: 10 ₉ /m ² ) 3 g Methyl ethyl ketone 200 g The above resin mixture was applied to an epoxy resin/glass cloth laminate to form an adhesive layer with a thickness of 40 μ. This adhesive-coated laminate was chemically plated with copper to a thickness of 30 μm using a conventional additive method. Comparative Example 1 NBR 50g Resol type phenolic resin 50g Silica (particle size 3-5μm) 3g Methyl ethyl ketone 200g Using the above resin mixture, 30μm epoxy resin/glass cloth laminate was coated in the same manner as in Example.
Chemical copper plating was carried out. Comparative Example 2 NBR 50g Epoxy resin 50g Curing agent (dicyandiamide) 5g Talc (particle size 3-5μm) 3g Methyl ethyl ketone 200g Using the above resin mixture, 30μm epoxy resin/glass cloth laminate was applied in the same manner as in Example.
Chemical copper plating was carried out. The properties of the chemical copper-plated laminates obtained in each of the above examples are shown in Table 1. 【table】

Claims (1)

[Claims] 1. An adhesive for additive plating made of a curable resin containing synthetic rubber, characterized in that it contains an inorganic filler surface-treated with a resol type phenolic resin or a fatty acid.